Edited by: Rodrigo Orlando Kuljiš, Leonard M. Miller School of Medicine, United States
Reviewed by: Daniel Ortuño-Sahagún, Centro Universitario de Ciencias de la Salud, Mexico; Richard Camicioli, University of Alberta, Canada
*Correspondence: Elisa H. Kozasa
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Yoga, a mind-body activity that requires attentional engagement, has been associated with positive changes in brain structure and function, especially in areas related to awareness, attention, executive functions and memory. Normal aging, on the other hand, has also been associated with structural and functional brain changes, but these generally involve decreased cognitive functions. The aim of this cross-sectional study was to compare brain cortical thickness (CT) in elderly yoga practitioners and a group of age-matched healthy non-practitioners. We tested 21 older women who had practiced hatha yoga for at least 8 years and 21 women naive to yoga, meditation or any mind-body interventions who were matched to the first group in age, years of formal education and physical activity level. A T1-weighted MPRAGE sequence was acquired for each participant. Yoga practitioners showed significantly greater CT in a left prefrontal lobe cluster, which included portions of the lateral middle frontal gyrus, anterior superior frontal gyrus and dorsal superior frontal gyrus. We found greater CT in the left prefrontal cortex of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group.
Aging is associated with changes in brain structure and function that may lead to cognitive losses, physical and behavioral changes (Persson et al.,
Yoga involves the practice of postures, breathing exercises and meditation. While branches of yoga adopted in the West have a strong physical component (postures and breathing exercises), yoga is not limited to the physical body. By definition, yoga is a meditative activity embodied in physical postures in which an attentional component must be present (Taimni,
Its intrinsic and unique contemplative characteristics distinguish it from typical forms of physical exercise, which are limited to the physical body. Ross and Thomas (
Twenty-one female hatha yoga practitioners who practiced at least twice a week for a minimum of 8 years, were recruited from hatha yoga studios in São Paulo, Brazil. Hatha Yoga, one of the most common yoga branches in the West, is based on asana (postures), pranayama (breathing exercise) and dhyana (meditation). We also recruited an additional group of 21 women who were naive to yoga, meditation or any mind-body intervention and were matched to the first group in age, years of formal education and level of physical activity. Subjects were matched for physical activity based on the practices of the Yoga group—those who did not practice any activity other than yoga were matched to sedentary controls and those who practiced yoga plus another physical activity were matched to a control group member who practiced the same or equivalent physical activity. Inclusion criteria were: at least 60 years of age, female, right-handed and having completed at least elementary school. We chose to include only women to add an element of homogeneity to the group. Interestingly, it was also easier to identify female yoga practitioners than male practitioners. Exclusion criteria were: substance abuse; tremor or dystonia of the head; chronic physical or other health problems that prevented them from performing their daily activities independently; any contraindication to MRI; a clinical history of neurological and/or psychiatric diseases. All volunteers provided written informed consent and the study was approved by the Institutional Review Board of Hospital Israelita Albert Einstein (CAAE 22313813.7.0000.0071).
Instrumental Activities of Daily Living—IADL: scores range from 9 (low function) to 27 (high function). Items are evaluated regarding individuals’ ability to perform each task (independently, with others’ help, or not at all; Lawton and Brody,
Beck Depression Inventory—BDI: self-report questionnaire with 21 multiple choice questions addressing several depression symptoms. Scores range from 0 to 63 (Beck,
Mini Mental State Examination—MMSE: test that evaluates several domains of cognitive function, such as spatial and temporal orientation; calculation; immediate and evoked memory; language-naming; writing; repetition and copying a drawing. Scores range from 0 to 30 (Folstein et al.,
Anthropometric measurements—Weight and height were measured.
A T1-weighted MPRAGE sequence was acquired for each participant using a Siemens 3.0T Magnetom Tim Trio System with a 12-channel head receive coil (matrix 1 × 1 × 1 mm voxel, TR = 2500 ms, TE = 3.45 ms, FOV = 265 mm, inversion time = 1100, flip angle = 7 degrees). Image quality was visually inspected immediately after each structural acquisition to control for motion effects and other artifacts.
The FreeSurfer analysis suite (v5.3.0 release
Whole-brain CT analysis was then performed on each vertex using the general linear model (GLM) embedded in the SurfStat toolbox
Data obtained from questionnaires and anthropometric measurements were analyzed using the SPSS 17.0 program (SPSS Inc., Chicago, IL, USA). Variables were compared using Student’s
The yoga group had 14.9 years of hatha yoga practice, on average. There were no significant differences between groups in terms of age, years of education, questionnaire scores or anthropometrical measures, as shown in Table
Group characteristics.
Control Group ( |
Yoga Group ( |
||
---|---|---|---|
Age (years) | 67.9 (1.004) | 66.2 (0.98) | 0.24 |
Years of Education | 14.6 (0.42) | 14.1 (0.42) | 0.35 |
BMI, kg/m2 | 25.3 (0.63) | 24.5 (0.92) | 0.53 |
BDI | 7.4 (1.2) | 5.3 (0.98) | 0.18 |
MMSE | 28.8 (0.28) | 28.1 (0.38) | 0.16 |
IADL | 26.8 (0.14) | 26.9 (0.04) | 0.14 |
Years of yoga practice | 0.0 | 14.9 (1.77) |
Relative to controls, yoga practitioners (i.e., female yoga practitioners) showed a significantly greater CT in a left prefrontal lobe cluster (cluster forming threshold
Differences in cortical thickness (CT) between yoginis and controls (
Anatomical and statistical information of the cluster in which significant between-group differences in cortical thickness (CT; i.e., yoga practitioners > Controls) were detected.
Region | Side | Talairach/MNI Coordinates | Peak vertex |
||
---|---|---|---|---|---|
Middle frontal gyrus | L | −35/−35 | 47/49 | 10/10 | 4.85 |
Superior frontal gyrus | L | −20/−20 | 54/57 | 15/17 | 3.06 |
In the present cross-sectional study, we observed greater CT in the left prefrontal cortex (middle and superior frontal gyri) of healthy elderly women who trained yoga for a minimum of 8 years compared with women in the control group. The present results parallel those previously reported in which younger yoga and meditation practitioners had greater GM volumes than non-practitioners compared to non-practitioners in the following brain regions: larger GM volume in the right anterior insula and right inferior temporal gyrus (Hernández et al.,
To the best of our knowledge, this is the first imaging study showing greater CT in elderly female yoga practitioners relative to controls. The greater thickness was observed in left prefrontal lobe areas associated with attention and other executive functions (Jeon,
Other attentional tasks such as video game playing, cause changes in cognition in older adults (Toril et al.,
Attention-Deficit/Hyperactivity Disorder (ADHD) is related to differences in brain structure and function when compared to controls (Batty et al.,
Our study has some limitations. Ideally, individuals across groups should have performed the same physical activities (other than yoga). Matching participants on this variable proved to be very difficult. Thus, we matched as best we could based on relative physical effort. Furthermore, as the number of participants in each group was relatively small, it did not allow us to make comparisons between individuals from different ethnic groups. Also, our volunteers performed only one MRI scan. Future studies should involve longitudinal randomized controlled trials and correlations with other peripheral measures.
In conclusion, healthy elderly women who practiced hatha yoga for at least 8 years had greater prefrontal CT than a group of matched controls. This CT may be associated with cognitive preservation.
RFA: acquisition of data; design; interpretation; revising and final approval of the article; agreement to be accountable for all aspects of the work. JBB and JRS: analysis; revising and final approval of the article; agreement to be accountable for all aspects of the work. SL and SSL: interpretation; revising and final approval of the article; agreement to be accountable for all aspects of the work. NI: acquisition of data; final approval of the article; agreement to be accountable for all aspects of the work. DFS: interpretation; final approval of the article; agreement to be accountable for all aspects of the work. EA: revising and final approval of the article; agreement to be accountable for all aspects of the work. EHK: conception and design of the work; analysis and interpretation of data; revising and final approval of the article; agreement to be accountable for all aspects of the work.
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
We would like to thank Telma Busch and Michel Naslavsky for their technical support.
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